Contoured adhesive wafer for ostomy appliance

ABSTRACT

An adhesive wafer for an ostomy pouch, and the combination of such a wafer and pouch, in which the adhesive layer of the wafer is composed of a hydrocolloid-containing skin barrier material and is contoured to provide a relatively thick body portion surrounded by a relatively thin peripheral portion, are disclosed. The wafer has a stoma-receiving opening, and the adhesive layer is of developed shape so that most, if not all, of the relatively thick body portion is located immediately below and to the sides of the stoma-receiving opening. The relatively thin peripheral portion of the adhesive layer is preferably embossed to provide a pattern of discrete, non-connecting depressions separated and isolated from each other by flat-top ridges dimensioned and arranged so that a skin surface engaged by said embossed surface primarily contacts only such ridges.

RELATED APPLICATION

This application is a division of application Ser. No. 08/718,955, filedSep. 26, 1996, now U.S. Pat. No. 5,730,736, which is acontinuation-in-part of copending application Ser. No. 08/640,008, filedApr. 30, 1996.

BACKGROUND AND SUMMARY

Adhesive wafers in which the adhesive material has hydrocolloidparticles dispersed therein, and is moisture absorbing as well asproviding both dry and wet tack, are well known for use as wounddressings and as the attachment faceplates for ostomy appliances. Whenused as the faceplate for an ostomy appliance, such a wafer is providedwith a stoma-receiving opening and has a backing layer that is securedeither permanently or detachably to a collection pouch for receivingstomal discharge. The hydrocolloid-containing adhesive layer, commonlyreferred to as being composed of skin barrier material, is intended tomaintain a liquid-tight seal against peristomal skin surfaces to preventleakage of waste material and protect such skin surfaces from theexcoriating effect of digestive fluids. In ileostomy cases where thestomal discharge is from the small intestine, the digestive liquids arestill active and are capable of serious injury to skin surfaces unlesssuch surfaces are adequately protected by the soft adhesive barriermaterial.

The period of time such an adhesive wafer may remain in contact with theskin before being replaced by a fresh wafer depends in part on the ratein which the barrier material becomes hydrated and degraded by contactwith stomal fluid. Other things being equal, an adhesive layer that isrelatively thick might be expected to degrade more slowly and provide alonger duration of protection against leakage and possible injury to thewearer's skin. However, it is also known that a wafer in which theadhesive material is too thick may be incapable of conforming withanatomical contours, and of changes in such contours as a patient movesabout, creating the possibility that channels may develop between thewafer and the skin and leakage may result. To reduce or eliminate suchpossibilities, wafers are now made in a contoured configuration with theadhesive material immediately surrounding the stoma-receiving openingbeing relatively thick and then tapering outwardly into a relativelythin peripheral flange portion that will remain sealed to the skin evenafter periods of vigorous wearer movement.

In our copending application, we disclose a contoured wafer in which theadhesive material of the outer flange portion is embossed in such a wayas to limit the extent of surface contact with the skin and, even moresignificantly, to render it unlikely that the same skin surfaces will becontacted to the same extent when the wafer is removed and replaced by afresh wafer. Specifically, the bodyside surface of the wafer's adhesivelayer is embossed to provide a pattern of small, discrete,non-connecting depressions or recesses separated and isolated from eachother by flat-top skin-contacting ridges. When the wafer is in place,skin surfaces engaged by the embossed surface primarily contact only theridges. The pattern of embossing renders it highly unlikely that onlythe skin areas contacted by a removed wafer will again be contacted by afresh replacement wafer, since even slight lateral or rotationaldisplacement in the position of the fresh wafer will bring its ridgesinto adhesive contact with skin surfaces not engaged by the previouswafer. The result is a wafer of enhanced skin friendliness whichpromotes healing, or at least avoids or reduces irritation, of theisolated skin areas underlying the depressions and which eliminates orreduces the possibilities that surface layers of skin will be strippedaway as an adhesive wafer is removed.

An important aspect of the present invention lies in the discovery thatthe effectiveness of an adhesive wafer may be further enhanced if theincreased thickness of barrier material is provided in certain locationswhere it is needed most, allowing for more barrier material to belocated where fluid exposure is expected to be substantial and lessbarrier material in those areas where such exposure is expected to berelatively slight. The result is a contoured wafer in which the adhesivematerial of greater thickness is found principally beneath and to thesides of the stoma-receiving opening.

The body portion of greater barrier thickness may extend completelyaround the stoma-receiving opening, but with a greater mass of barriermaterial located below and to the sides of that opening, or it mayassume a crescent shape so that the greater thickness is found onlybelow and to the sides of the opening. In either case, in a circulararea of reference concentric with the stoma-receiving opening, thequantity of barrier material in the semicircular lower half of thatreference area exceeds the quantity in the upper half because of thedifferences in barrier thickness.

By concentrating the barrier material of greater thickness in criticalareas, a wafer embodying the invention having the same amount ofrelatively expensive barrier material as a conventional wafer can beexpected to have increased effectiveness in terms of skin protection andleakage prevention. By embossing the relatively thin outer peripheralportion of the adhesive layer, material costs are additionally reducedwhile providing increased skin friendliness because of the unlikelihoodthat only skin areas contacted by a removed wafer will again becontacted by a replacement wafer.

Other features, advantages, and objects of the invention will becomeapparent from the specification and drawings.

DRAWINGS

FIG. 1 is a rear elevational view of an ostomy appliance embodying theinvention.

FIG. 2 is an enlarged sectional view taken along line 2--2 of FIG. 1.

FIG. 3 is an enlarged fragmentary elevational view illustrating thebodyside face of the wafer in relation to a circle of reference.

FIG. 4 is a rear elevational view of an appliance constituting a secondembodiment of the invention.

FIG. 5 is an enlarged fragmentary sectional view taken along line 5--5of FIG. 4.

FIG. 6 is a fragmentary elevational view illustrating critical portionsof the wafer in relation to a circular line of reference.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1-3 of the drawings, the numeral 10 generallydesignates an ostomy appliance comprising a pouch 11 and an adhesivewafer 12 serving as the faceplate for adhesively attaching the applianceto the peristomal skin surfaces of a patient. The pouch 11 isconventional, being essentially composed of a pair of side walls 11a and11b of thermoplastic film sealed to each other along their edges 13.While the pouch is shown as being heat sealed along all of its edges, itmay optionally be provided with a drainage opening at its lower end.Such opening, if provided, may be closed by a suitable clamp of the typedisclosed in U.S. Pat. No. 3,523,534 or, alternatively, may be equippedwith a valve as disclosed, for example, in U.S. Pat. Nos. 3,598,150 and4,280,498. The pouch may be formed of a film composed of any suitableheat-sealable plastic or combination of plastics (e.g., as a coextrudedlaminate) that is tough, flexible, and liquid and gas impermeable, allas well known in the art. One such film found to be particularlyeffective is a coextrusion of polyethylene and polyvinylidene chlorideavailable under the trademark "Saranex" from Dow Chemical, Midland,Mich., but other films having similar properties may be used.

Wafer 12 is in the form of a disc which is illustrated in FIG. 1 asbeing generally circular in shape but, if desired, other configurationsmay be selected. As shown in FIG. 2, the wafer essentially comprises anocclusive adhesive layer 14 and a backing layer 15. The adhesive layeris generally planar and has a rear or bodyside surface 14a and a frontor pouchside surface 14b. The flexible backing layer 15 covers thepouchside surface 14b and a removable release sheet 16 composed ofsiliconized paper, silicone-coated plastic, or other material whichresists strong adherence to the adhesive material, covers surface 14a(the release sheet is shown only in phantom in FIG. 2). Astoma-receiving opening 17 extends through layers 14 and 15 and may bepre-sized to fit the patient or, alternatively, may be provided as astarter opening capable of being enlarged by the user (with scissors) toprovide a re-formed opening that is sized and configured to match thepatient's stoma.

Backing layer 15 must be flexible and may also be stretchable andcontractable for purposes of anatomical conformity. It may be in theform of a film of polyurethane, polyethylene, or other suitablethermoplastic material. Alternatively, it may be a soft, flexiblethermoplastic foam of closed, semi-open, or fully-open cellconstruction. Polyurethane or polyethylene foams are believed suitable,but other thermoplastic foams having similar properties may be used.Particularly effective results are obtained where the backing layer 15is gas pervious and formed of a soft, porous non-woven fabric ofthermoplastic fibers such as, for example, a non-woven fabric ofspun-bonded polyethylene fibers. One such fabric is marketed under thedesignation P80-00 by Corovin GmBh, Peine, Germany, but other non-wovenfabrics having similar properties may be used. The backing layer 15 ispermanently joined to wall 11b of the pouch by one or more annular heatseals 20 surrounding the stoma-receiving opening 17.

Adhesive layer 14 is a moisture-absorbing and moisture-swellable skinbarrier material having a continuous phase composed of one or more tackyelastomers and a discontinuous phase consisting essentially of particlesof one or more hydrocolloids dispersed throughout the adhesive layer.Typical hydrocolloids are pectin, gelatin and sodium or calciumcarboxymethylcellulose, but other hydrocolloids such as karaya may beused. If desired, superabsorbents may be included in the skin barrierformulation. The continuous elastomeric phase may be composed of atacky, deformable elastomeric material such as polyisobutylene and/or ablock copolymer such as a styrene-isoprene-styrene copolymer of the typedescribed in U.S. Pat. Nos. 4,738,257 and 4,231,369. Tackifiers,plasticizers, extenders and stabilizers may be included, all as wellknown in the art.

A characteristic feature of wafer 12 lies in the fact that it iscontoured to provide a relatively thick body portion 22 adjacentstoma-receiving opening 17 and a relatively thin peripheral portion 23.In the drawings, the contouring is shown along only the bodyside surface14a with the pouchside surface 14b being relatively flat or planar;however, if desired, the contouring may be provided along both surfacesor, in some cases, along only the pouchside surface. Thicknessdimensions of the body and peripheral portions may be variedconsiderably depending on factors such as the particular barrierformulation selected and the expected wear time for such a wafer but, ingeneral, the thickness of the peripheral portion should be less than 0.5mm, preferably no more than 0.3 mm, and the body portion should have athickness more than 0.5 mm, and preferably 1.0 mm or more. The thinnessof the peripheral portion allows the adhesive barrier material toconform to folds and irregularities in skin surfaces and to remain insealing contact with such surfaces as a patient moves about, whereas therelatively thick body portion functions to maintain a soft, pliant,liquid-tight seal about the patient's stoma.

Body portion 22 is located at the edge of stoma opening 17 and may, ifdesired, extends completely about that opening. In the embodimentillustrated, the thick body portion 22 is somewhat crescent-shaped andextends only beneath and to the sides of opening 17. Whether the thickbody portion surrounds the opening or extends only beneath and to thesides of that opening, a greater quantity of adhesive barrier materialis located beneath the opening than above it. The result is an adhesivewafer in which the greater thickness of skin barrier material isconcentrated in the areas of the wafer where it is needed most. With anostomy pouch worn in the orientation depicted in the drawings, fluidsdischarged into the pouch through stoma opening 17 tend because ofgravitational influences to make greater contact with the barriermaterial exposed along the lower edges of opening 17. The rate ofhydration of the barrier material along the lower portions of theopening also tends to be greater but, because a greater quantity ofabsorbent barrier material is concentrated in that location, suchhydration may proceed with less risk of leakage and with thepossibilities of longer wear time for a wafer having the same amount ofbarrier material as a conventional wafer.

The greater quantity of barrier material located immediately beneath andto the sides of opening 17 may be best understood from FIG. 3. Stomaopening 17 is shown to be concentric with the outer edge 12a of wafer 12although, if desired, the opening may be slightly above (or even below)center and the wafer may be non-circular in outline. Phantom line 26defines a circular area of reference that is concentric with stomaopening 17. The radius "r" of the circular area of reference 26 is equalto the distance from the center 27 of the opening to the lowermostlimits 28 of the relatively thick body portion 22. As shown in FIG. 3,the circular area of reference 26 is divided by line 29 into upper andlower halves 26a and 26b of equal area. A fundamental aspect of thiswafer construction is that the quantity of skin barrier material in thelower half 26b is substantially greater than the quantity in upper half26a. By "substantially" is meant that the quantity of skin barriermaterial in the lower half 26b of the circular zone of reference 26 isat least 10% more, and preferably at least 30% more, than in the upperhalf 26a. Such is the case regardless of whether the relatively thickbody portion of barrier material extends completely about opening 27 oronly below and to the sides of that opening as depicted in the drawings.

In the embodiment of FIGS. 4-6, pouch 11' is non-symmetrical in outlinebut is otherwise similar in construction to the pouch of the firstembodiment. Wafer 12' is non-circular in outline and includes adhesivelayer 14' and backing layer 15' having compositions similar to thosealready described. The adhesive layer 14' is contoured, having arelatively thick body portion 22' and a relatively thin peripheralportion 23', each being of the thickness ranges previously discussed. Itwill be noted, however, that the bodyside surface of peripheral portion23' is embossed to provide a pattern of discrete, non-connectingdepressions or recesses 30 separated and isolated from each other byridges or shoulders 31. The depressions are preferably round in outline,although they may assume other shapes if desired, and are shown to bearranged in a non-rectilinear pattern of random appearance. The ridges31 are flat-topped for adhesively contacting and sealingly engaging askin surface surrounding a stoma. The flat tops of the ridges aregenerally coplanar with each other, and the depressions 30 aresufficiently deep so that when the wafer is in use the skin surfacecontacted by the adhesive layer tends to bridge the depressions.

As shown in the drawings, the bodyside surface of the relatively thicknon-embossed portion 22' is smooth to insure greater sealingeffectiveness with skin surfaces immediately surrounding a patient'sstoma. The thickness of the non-embossed body portion 22' should be atleast as great as the thickness (i.e., axial extent) of the ridges 31 ofthe embossed peripheral portion 23'; in the illustration given, thethickness of body portion 22' is substantially greater to enhance themoisture-absorbing capacity of the zone surrounding stoma-receivingopening 17'.

The depressions 30 are non-communicating to prevent channeling andleakage and are dimensioned and arranged to make it highly unlikely thatthe depressions and ridges of a replacement wafer will assume the samepositions in relation to the skin as those of a wafer being replaced. Inother words, when the wafer is in place, a skin surface engaged by theembossed peripheral portion primarily contacts only the ridges 31. Thesurface of the skin tends to bridge the depressions 30, with the resultthat only a fraction of the area of the embossed surface directlycontacts the skin. The pattern of embossing renders it highly unlikelythat only the skin areas contacted by a removed wafer will again becontacted by a fresh replacement wafer, since even slight lateral orrotational displacement in the position of the fresh wafer will bringits ridges into adhesive contact with skin surfaces not engaged by theprevious wafer. The result is a wafer of enhanced skin friendlinesswhich promotes healing, or at least avoids or reduces irritation, of theisolated skin areas underlying the depressions and which eliminates orreduces the possibilities that surface layers of skin will be strippedaway as the adhesive wafer is removed.

As shown most clearly in FIG. 4, the relatively thick body portion 22'of the adhesive layer is generally circular in outline and surroundsstoma opening 17' although, as described in connection with thepreceding embodiment the body portion need not be circular or annular.What is important is that opening 17' and body portion 22' arenon-concentric, with the opening being above center in relation to thebody portion 22'. The result is a construction in which a substantiallygreater quantity of adhesive barrier material is located beneath opening17' than above it.

FIG. 6 is a diagramatic view similar to FIG. 3 and shows stoma opening17' concentric with a line 26' defining a circular area of reference.The outer periphery of the relatively thick body portion 22' of adhesivelayer 14' is indicated by line 22a'. As in the previous embodiment, itwill be observed that the bulk of the thicker body portion 22' of theadhesive layer is located below the horizontal line 29' that divides thecircular area of reference into semi-circular upper and lower portions26a' and 26b'. As previously described, the lower half 26b' of thecircular zone of reference therefore contains substantially more skinbarrier material than upper half 26a.

Two embodiments have been disclosed for purposes of illustration, and itis to be understood that features disclosed in connection with oneembodiment may be utilized with the other embodiment. For example, whilethe embodiment of FIGS. 1-3 is depicted with a wafer having an adhesivelayer 14 with a peripheral portion having a smooth bodyside surface 14a,that surface may be embossed to provide a pattern of discrete,non-connecting depressions or recesses in the same manner as shown anddescribed in connection with the embodiment of FIGS. 4-6. Other featuresmay also be combined or modified without departing from the spirit andscope of the invention.

We claim:
 1. A wafer for adhesively attaching an ostomy appliance toperistomal skin surfaces of a wearer, said wafer having an adhesivelayer consisting of water-absorbing and water-swellable skin barriermaterial in which particles of one or more hydrocolloids are dispersedin a soft, pliant adhesive medium, and a flexible backing layer forattaching said wafer to a collection pouch; said adhesive layer beingcontoured and having a thin peripheral portion and a thick body portion;said wafer having a stoma-receiving opening surrounded by a circulararea of reference having a perimeter concentric with said opening and aradius equal to the distance from the center of said opening to thelowermost limits of said thick body portion; said circular area ofreference including semicircular upper and lower halves wherein saidlower half contains a greater quantity of skin barrier material thansaid upper half.
 2. The wafer of claim 1 in which said thick bodyportion of said adhesive layer surrounds said stoma-receiving opening.3. The wafer of claim 2 in which said thick body portion of saidadhesive layer has a circular periphery; said stoma-receiving openinghaving its center spaced above the center of the circle defining theperiphery of said body portion.
 4. The wafer of claim 1 in which saidthick body portion of said adhesive layer is crescent-shaped and islocated entirely below and to the sides of said stoma-receiving opening.5. The wafer of claims 1, 2 or 4 in which said semicircular lower halfof said circular area of reference contains at least 10% more skinbarrier material than said upper half.
 6. The wafer of claim 1, 2 or 4in which said thin peripheral portion of said adhesive layer has abodyside surface thereof embossed to provide a pattern of discrete,non-connecting depressions separated and isolated from each other byskin-contacting ridges dimensioned and arranged so that a skin surfaceengaged by said embossed surface primarily contacts only said ridges ofsaid adhesive layer.
 7. The wafer of claim 6 wherein said ridges haveflat and co-planar skin-contacting surface portions.
 8. The wafer ofclaim 6 wherein said depressions are arranged in a non-rectilinearpattern of random appearance.
 9. The wafer of claim 7 wherein at leastsome of said depressions are round in outline.
 10. The wafer of claim 1wherein said backing layer is gas-pervious.
 11. The wafer of claim 10wherein said backing layer comprises a porous non-woven fabric.
 12. Thewafer of claim 6 in which a removable protective release sheet coversthe surface of said adhesive layer opposite from said backing layer. 13.The wafer of claim 12 in which said release sheet includes ridges anddepressions that conform with the embossed contour of said adhesivelayer.